Are you trying to be funny? Reach offers an advantage from a distance. Skills and speed also play a role.
Reach offer an advantage if you know how to use and enforce it. The same advantages can be had from timing and speed, that is controlling the distance. These are not static, Rock-em, Sock-em robots here but fluid athletes. It's not as simple as jousting.
I completely understand. But in fencing or jousting the equipment used is an equal length, correct? If one person had a 30" sword and the other had a 36" sword it would not be fair. Yet we see this in boxing all the time when one fighter has a significant reach advantage over the other. The taller man with the greater reach can hit and not be hit from a certain range. In boxing, the examples of a shorter man with less reach out jabbing a much taller man with a longer reach when both are ranked are pretty rare. This isn't an accident.
Being able to hit any opponent is a function of speed timing and skill. This is why prime Tyson could outjab much bigger opponents.
Errors regarding fighters reach are comonplace in all eras. It only takes one mistake, exageration or typo, and it can get quoted and requoted. Establishing the truth should not be that hard. You just look at the sources closest to the tape measure, and you get a good idea.
Now correct if I am wrong but the reach is the measured wingspan when you hold out each arm at shoulder level at a 90 degree,parallel to the ground and the reach measurement is taken from the fingertip on one hand across the chest/back to the fingertip on the other outstretched arm? Now since no boxer fights in such a stance, wouldn't it be more accurate to simply measure the length of the arm and give that measurement as the reach? It may be that one boxer has longer arms but the other boxer is given the same or greater reach because he has a bigger chest/torso.
The week before the third Johnson McVey fight in San Francisco the hosting Shasta Club measured the fighters and among their posted and published results listed Johnson's reach at 76" to McVey's at 77" ..